Core-spun yarn reenforced composite products



July 11, 1961 R. s. GOY 2,992,150

CORE-SPUN YARN REENFORCED COMPOSITE PRODUCTS Filed Oct. 2, 1956INVENTOR. PoNeLD STQNSFIELD 60* BY @4 1 $02M FITTOENE Y r' 2,992,150 1CPatented July-11, 1961 CORE-SPUN YARN REENFOROED COMPOSIT PRODUCTSRonald Stans'field Goy, Castle Bromwich, near Birmingham, England,assignor to 'Dunlop Rubber Company Limited, London County, England, aBritish company Filed Oct. 2, 1956, Ser. No. 613,368 Claims-priority,application Great Britain Oct. 4, 1955 1 4 Claims. (Cl. 1'54-5.2)

This invention relates to composite products containing textile yarnsand plastic compositions having a basis of a polyvinyl compound.

Cotton yarns stick naturally to plastic compositions due to theirfibrous nature, the hairs of the cotton staple giving in effect amechani 1 1 look. On the other hand continuous filament yarns made, forexample, of regenerated cellulose, nylon or polyesters require to behotstretched to avoid subsequent deformation and then have to be treatedwith a bonding agent in order to make them adhere satisfactorily.

Artificial staple fibre yarns are produced from rayon, nylon or likematerial by cutting filaments thereof into staple form and spinning thestaple fibre thus formed. Such yarns can also be used as a reinforcementbut they are generally not so strong as and have a higher extensibilitythan comparable yarns made of continuous filaments. Moreover it has beenfound that the force necessary to break down the adhesion between theyarn and the composition is normally proportional to the strength of theindividual fibres forming the yarn and therefore with the weaker orstaple fibres, e.g. rayon, adhesion is less satisfactory than with thestronger fibres e.g. nylon.

It has now been found that if continuous filaments and staple fibres arespun together by the process known as core-spinning or Belgian doubling,the continuous filaments being used in a proportion of from 50% to 90%by weight, yarn may be produced which will adhere better to plasticcompositions having a basis of polyvinyl compound than yarn formedsolely of continuous filaments and which still possesses a satisfactorytenacity. Moreover the tenacity of the core-spun yarn is found to beapproximately equal to the sum of the tenacities of yarns obtained byspinning each of the components separately.

According to the present invention therefore a composite materialcomprises core-spun yarns comprising continuous filamentary materialtwisted together with staple fibres, the proportion of continuousfilamentary material being between 50% and 90% by weight, embedded in aplastic composition having a basis of a poly vinyl compound.

The construction of the core of spun yarn and of a belting embedding itare shown in the accompanying drawings in which FIG. 1 is a side view ofa portion of the yarn, a part of the outer spun yarn being shown asremoved at one end to show the structure of the core, and

FIG. 2 is a cross-section of a rubber belting showing the position ofthe yarn or thread either as separate longitudinally extending threadsor as a fabric having such threads as warp and light weft.

In the core of spun yarn of FIG. 1 the core is made of a number offilaments 11 having a twist and extending longitudinally of the yarn.These filaments are of continuous filamentary material. Spun on thiscore is a layer of staple fibres 12.

In the section of FIG. 2 cords 13 of the type illustrated in FIG. 1 areembedded in a mass 14 of the plastic composition. The cords 13 may be inthe form of longitudinally extending warp having filler threads 15.

continuous filament yarn is The invention is of particular importance inthe production of belting made of a polyvinyl chloride compositionreinforced by a'textile material, since it makes it possible to obtainthe advantages both of continuous filament yarns and also of staplefibre yarns. Thus a yarn made by core-spinning a continuous filamentnylon or Terylene yarn with cotton fibres possesses both the hightenacity of the core yarn together with the good bonding properties ofcotton yarns for polyvinyl chloride compositions, so that by using suchyarn conveyor or transmission belting can be obtained having the highstrength obtainable with nylon or Terylene reinforcements and the goodadhesion between the reinforcement and the composition obtainable withcotton or other staple fibre yarn.

Filamentary materials which may be used include those made ofregenerated cellulose, nylon or the polyester sold under the registeredtrade mark Terylene, and the staple fibres may be of such materials ormay be natural fibres e.g. cotton.

Furthermore, the filaments and the staple fibres in a yarn may be ofsimilar or dissimilar materials. For example rayon, nylon or Terylenefilaments may be spun with a layer of cotton staple. Other suitablecombina tions are, nylon filaments and nylon staple, rayon filaments andrayon staple. Terylene filaments and Terylene staple, Terylene filamentsand nylon staple, and nylon filaments and Terylene staple.

In core-spinnmg or Belgian doubling the yarn spun on a conventionalspinning frame. The staple fibre, in roving form, is drafted in theusual manner and the twisted with the staple. By correctly balancing thetwists, a layer of staple fibre is formed round the centre core of thecontinuous filament. If the continuous filament is nylon then bycore-spinning with a low extensibility staple fibre, e.g. cotton, theadditional advantage is obtained that the extensibility and creep of thecomposite yarn is lowered and the necessity for hotstretching is reducedor eliminated, the tendency towards heat shrinkage being also reduced.

Preferably the yarn comprises between 20% and 40% staple fibre thoughthe proportions of continuous filament to staple may be varied providingthe latter does not exceed 50% of the yarn. In respect it has been foundthat yarns constituted by 70% Terylene and 30% cotton, or 60% nylon and40% cotton provide, when doubled, satisfactory cords.

An example of suitable yarn for use in conveyor belting is as follows:

The basic yarn was made by core spinning 215 0 denier Terylene with 30scotton roving to a resultant yarn count of 12s. The core-spun yarn wasthen doubled twelve fold and the doubled yarn cabled four fold to give a12s/ 12/ 4 construction.

The cabled cord had a tensile strength of 225 1b. and its compositionwas approximately 60% Terylene and 40% cotton.

The calculated strength of the continuous filament Terylene in the cordis 172 1b.

The cotton used was combed Egyptian Karnak of Fully Good Grade. A 30s/12/ 4 cord from this type of cotton should have a strength ofapproximately 53 1b., i.e. the difi'erence between the strength of theblended cord and that of the calculated strength of its Terylenecomponent.

The cord thus develops the combined strength of the two components.

The twist particulars were as follows:

'Iwist/1"-single 12.0 Z (core-spun) 'I wist/ "-first folding 5.0 STwist/l"seeond folding 2.0 Z

fed in at the front roller and- Conveyor belting fabric of the followingconstruction was made with this cord as the warp and with a continuousfilament nylon Weft.

Threads/1" Warp 13 Weft 8 Plies:

Warp 12s/12/4 Weft 210 denier/ 8/ 3 Weight/square yard 52.0 oz.

The finished belting fabric had a tensile strength of 2,100 lb./1 ply inthe warp direction and 540 lb. per inch in the weft direction.

Belting may be made by impregnation of this fabric with a flexiblepolyvinyl composition consisting of:

Parts by weight Polyvinyl chloride 60 Tritolyl phosphate 20 Dioctylphthalate Stabiliser 5 Colour and fillers 5 and. applied to the fabricin known manner such as by spreading or by calendering on a frictioncalender. The.

ticiser, e.g. a mixture of tritolyl phosphate and dioctyl phthalate.

Having now described my invention, what I claim is: 1. A compositematerial comprising a plastic composition having a basis of a polyvinylcompound selected from the group consisting of polyvinyl chloride,copolymers of vinyl chloride and vinyl acetate and 'copolymers of vinylchloride and vinylidene chloride having embedded therein yarnscomprising a core of continuous filamentary material having a layer of aroving of staple fibres spun thereon wherein the proportion ofcontinuous filamentary material is between and by Weight of the yarn.

2. A composite material according -to claim 1 wherein the continuousfilamentary material of the core-spun yarns is nylon and the staplefibres are cotton fibres.

3. A composite material according to claim 1 wherein the continuousfilamentary material of the core-spun yarns is polyethyleneterephthalate and the staple fibres are cotton fibres.

4. The composite material of claim 1 in which said yarns are doubledyarns each having a core of filamentary material and having a layer of aroving of staple fibres wound thereon.

1. A COMPOSITE MATERIAL COMPRISING A PLASTIC COMPOSITION HAVING A BASISOF A POLYVINYL COMPOUND SELECTED FROM THE GROUP CONSISTING OF POLYVINYLCHLORIDE, COPOLYMERS OF VINYL CHLORIDE AND VINYL ACETATE AND COPOLYMERSOF VINYL CHLORIDE AND VINYLIDENE CHLORIDE HAVING EMBEDDED THEREIN YARNSCOMPRISING A CORE OF CONTINUOUS